Food manufacturers and processors in this country have some pretty smart marketers working for them. They know that many of us are trying to reduce the number of carbohydrates in our diet in order to lose weight and/or control our blood sugar levels. The rise of the Atkins diet and various forms of ketogenic diets has created an opportunity for these companies. They have recently created a term out of thin air: “net carbs.”
There is no scientific basis for this term. It is not used in any scientific literature. It is nothing more than a marketing term used to make us believe we can safely eat higher carbohydrate foods without worrying as much. It’s very likely great for the bottom line of the food companies, but not so good for your waistline.
“Net Carbs”, or sometimes called “Impact Carbs”, are calculated by taking the total number of carbohydrates found in a serving of a particular food, and then subtracting the fiber and sugar alcohols from that number.
In this example, a popular breakfast bar might advertise “2 Net Carbs”. Taking the Total Carbohydrates (19g) and subtracting both the Dietary Fiber (2g) and the Sugar Alcohol (15g) leaves a total of 2.
Dietary fiber is also sometimes referred to as “Good Carbs”. They are still carbohydrates, but they take a bit longer to digest and therefore do not spike the blood glucose as quickly. Said another way, these types of carbohydrates have a lower glycemic index.
Sugar alcohols, on the other hand, are modified alcohol molecules that resemble sugar. They are often used as artificial sweeteners.
So the logic is to take total carbohydrates, and simply discount the slower-digesting ones (fiber) and the artificial sweeteners (sugar alcohols).
The problem with this approach is that both fiber and artificial sweeteners DO have an effect on blood glucose and insulin levels. In fact, some sugar alcohols have been shown to raise blood insulin even higher and faster than glucose does.
It is disingenuous (at the least) to imply that fiber and sugar alcohols somehow “don’t count” when it comes to managing carbohydrate intake. If you are following a ketogenic diet, these substances WILL impact your ability to maintain ketogenesis. If you are simply trying to minimize carbohydrates, these substances will add to your total daily carb intake.